1. Field of the Invention
The present invention relations to unauthorized user prevention devices and methods. More particularly, the present invention relates to an identification device and method to prevent the discharge of a weapon by anyone other than an owner and/or registered user.
2. Description of the Related Art
All too often there are tragic news reports of people who are gravely injured or killed by gunshots fired by a person who is not the owner or an authorized user of the firearm. Some of these tragedies are accidental, such as when a child finds a parent""s firearm and accidentally discharges it at his/herself or at friends. Other tragedies concern firearms, which are taken during burglaries, which are subsequently, used in future robberies and/or homicides. On more than one occasion, a perpetrator has been known to wrestle the gun from an officer""s holster and use it against the officer.
Regardless of the specific cause, it is evident that many of these incidents could be avoided if the firearm were only fireable by the owner or other authorized user of the gun. In fact, there is in fact a current effort by citizens and lawmakers to require the inclusion of trigger locks on handguns.
U.S. Pat. No. 4,970,819 to Mayhak discloses a system for sensing the grip pattern of the hand of a potential user of a firearm and permits the firing thereof if it senses a particular grip pattern of an authorized user which it has been programmed to recognize. The system includes grip pattern sensing means on the handgrip of the firearm, a simulated neural network memory capable of recognizing a particular grip pattern and a microprocessor for accessing the neural network to inquire whether it recognizes the grip pattern being sensed by the sensing means. The microprocessor also controls means for permitting and preventing actuation of the firing mechanism of the firearm to allow the firearm to be discharged only when the grip pattern sensed by the sensing means is that of the authorized user which the simulated neural network memory has been programmed to recognize.
According to the ""819 patent, xe2x80x9ca simulated neural network does not possess a memory in the sense that a computer has a memory. Instead, the training of a pattern recognition neural network involves repeatedly subjecting its input neurons to signals corresponding to the pattern, including variations thereof. This establishes interconnections between the input neurons, the hidden neurons and the output neuron, so that, eventually, when the trained network is subjected to a pattern signal the output is either xe2x80x9cyesxe2x80x9d or xe2x80x9cnoxe2x80x9d that it is or is not the pattern it has been trained to recognize. A trained neural network will exhibit a particular pattern of interconnections between neurons therein and the pattern of connection strengths between neurons is equivalent to memory for that networkxe2x80x9d (col. 3 lines 34-48 of the ""819 patent).
Furthermore, according to the ""819 disclosure, xe2x80x9cArtificial neural networks mimic behavior of the brain in that they can be taught to recognize and distinguish between different patterns and shapes. Once the neural network has been trained to recognize a particular pattern, it can do so even though it later is presented with small variations or incomplete information about that pattern. The neural network is thus ideally suited for recognizing a particular handgrip pattern impressed on sensing means 23 even though the authorized user may place his hand in a slightly different location or apply slightly different pressures with each grip. The neural network can be trained to take such variations into account and still distinguish the grip pattern for which it is programmed from grip patterns created by others who are not authorized to use the firearmxe2x80x9d (from col. 3 lines 11-26 of the ""819 patent).
U.S. Pat. No. 5,603,179 discloses a xe2x80x9csafety mechanism for a firearm consisting of a specialized scanning mechanism built into the firearm""s trigger. The scanner is programmed to read the unique fingerprints of a given individual. The device is also capable of holding the programmed print information for more than one person, so that multiple people would he able to use the firearm. However, usage is limited to only those persons whose handprints have been prestored in the scanner. The scanner mechanism is connected to the firearm""s safety lock. The safety is prevented from being released without proper authorization from the scanner. When a person grips the weapon and places his finger on the trigger, the pressure of the finger on the trigger activates the scanner, and the scanner reads the fingerprint to determine if the scanned fingerprint matches one of the pre-stored fingerprint images. If the individual is an authorized user, the scanner transmits a signal to the safety, releasing this device and activating the firearm for usexe2x80x9d (from abstract of the ""179 patent).
U.S. Pat. No. 5,316,479 to Wong discloses a firearm training system, xe2x80x9cwhich allows the measurement and display as a function of time of the hand grip force pattern applied to the grip of a firearm by a weapon hand of a shooter. This permits the detection of variations in the individual handgrip forces in the pattern during firing of the weapon. This firearm training system preferably also provides for the detection and display as a function of time of the position of the firearm trigger. The system includes separate force transducers for the side and front-to-back grip forces applied to the side surfaces and one of the front and back surfaces of the grip respectively as well as a trigger position sensor. A relative value of the hand grip forces detected by the transducers and a relative trigger position detected by the sensor are graphically displayed by the system as a function of time.
Wong discloses a method of training a shooter by determining the grip pattern of the shooter""s weapon hand on a firearm by detecting a front-to-back grip force and a side grip force applied by the weapon hand and graphically displaying as a function of time a relative value of the front-to-back and side grip forces respectively. Thus, the system provides for a more effective training of a shooter, which substantially translates into cost savings in terms of training time and ammunition, especially since the firearm training system and method may effectively be used under both dry and live fire conditionsxe2x80x9d (See abstract of the ""479 patent). The time period disclosed by Wong is relatively fixed, for example, 100 ms snapshot for each user training with the weapon. Wong provides feedback so that a shooter can see a xe2x80x9ccorrectxe2x80x9d way to hold the weapon and pull the trigger, as opposed to xe2x80x9cincorrectxe2x80x9d grips that could impair accuracy. Thus, Wong teaches a shooter how to conform to a predetermined method of holding and firing a weapon.
The present invention is directed to a weapon discharge protection system. This system comprises a safety feature that prohibits a firearm, such as a handgun, from being fired by anyone other than its owner or other authorized person. In one embodiment, pressure sensors are arranged within the handgrip of the firearm. When one attempts to fire the firearm, he or she exerts a unique pressure signature profile on the handgrip. That is, each person exerts a pressure signature profile that is comprised of (1) the position of the hand on the gun handle; (2) pressure as a function of position on the gun handle; and (3) pressure as a function of time. Pressure signature profiles are sufficiently distinctive as a means for differentiating the owner or other authorized person, whose pressure signature profile is stored in memory, from the remainder of the population-at-large. This signature profile is most differentiating during the half of a second just prior to the trigger pull, as the user prepares to fire the weapon. Initial data show that no more than 1% of the population-at-large possess a given pressure profile. In other words, there is a very low probability that a person who is not the owner or authorized user of a gun would be permitted to fire the gun because he or she matched the stored pressure signature profile.
In one embodiment, quartz crystals, arranged along the surface of the handle, are used as the pressure sensors. Quartz crystals are an attractive option because they are relatively inexpensive and commercially available. When biased these crystals, which are used in timepieces, oscillate at a fixed frequency, and pressure applied to the crystals result in repeatable, precise changes in this oscillation frequency. Sensor elements, such as quartz crystals offer long-term stability, high rigidity, and good strength, and provide a wide measurement range over a wide range of temperatures.
The electrical signals from the quartz crystals, which correspond to the pressure signature profile, or other sensor material, is inputted to a processing unit, such as a microprocessor. The signal could be the electrical signal generated by the pressure signature profile of the lawful owner or user, inputted to the processing unit for the first time. In this case, by entering a sequence of commands, the signal will be stored within the processing unit as the pressure signature profile of the owner or authorized user. On the other hand, the signal generated by the pressure signature profile could be that of a person who is attempting to fire the firearm, in which case the electrical signal outputted from the crystals to the processing unit is compared to the signal stored as pressure signature profile of the owner or authorized user. If the signal matches the signal stored as pressure signal profile, then the processing unit activates a mechanism that allows the owner or authorized user to fire the firearm. If the signal outputted from the crystals does not match the signal stored on the pressure signal profile, then the processing unit does not activate the mechanism, so that the firearm cannot be fired.
According to a first aspect of the invention, an unauthorized user prevention apparatus for preventing unauthorized users from operating a particular device comprises
an interlocking unit for deactivating the particular device;
a plurality of pressure sensors for sensing a user""s handgrip on the particular device;
a comparator unit for comparing a pressure signature profile compiled from an output from said pressure sensors with at least one pressure signature profile in storage, wherein the at least one pressure signature comprises:
1) hand position of the user""s handgrip on the particular device as indicated by a change in pressure on at least one of the plurality of the pressure sensors;
2) pressure as a function of position on the particular device; and
3) pressure as a function of time;
a control unit/cpu for receiving an output from the comparator unit indicating that the signature profile compiled by the comparator unit matches said at least one pressure signature profile in storage,
wherein the control unit/cpu releases the interlocking unit upon receipt of a signal from the comparator that the pressure signature profile of the user""s handgrip on the particular device matches at least one pressure signature profile in storage.
In an embodiment, the particular device comprises a firearm, the interlocking unit comprises one of a latch unit and a push button safety unit; and the pressure sensors are arranged at least in a handle of the firearm.
The latch unit may comprises a solenoid, a latch, and a spring that biases the latch.
The latch unit can be arranged substantially inside the firearm, or on an exterior of the firearm. The latch can be biased to hold an existing safety of the firearm in a locked position.
In addition, latch unit may also unlock the existing safety of the firearm when the control unit/cpu releases the latch unit from the biased locked position.
In another aspect of the invention, the push button safety unit blocks movement of the safety button to release a trigger lock.
The pressure sensors can be adjacent an exterior surface of the particular device, and particularly arranged adjacent an exterior surface of a handle of the firearm.
In another aspect of the present invention, the sensors can be embedded in a cover which is arranged on at least a portion of an exterior surface of the particular device, such as a firearm.
There may be sensors additionally embedded in the trigger of the firearm. A fingerprint detection system of the prior art could be used in conjunction with the present invention as well.
According to another aspect of the invention, the sensors comprise a piezoelectric material, or they can be acoustic resonators.
The sensors may also comprise one of pressure strain gauges and micro-machined pressure sensors (MEMS).
In yet another aspect of the present invention, the particular device is a vehicle;
the interlocking unit comprises one of an ignition cut-off and a fuel cut-off unit; and
the sensors are arranged in a passenger compartment of the vehicle. For example, the sensors can be arranged to detect a user""s handgrip on a steering wheel, a dashboard, a gearshift knob, and/or a door handle.
In addition, the sensors can be embedded in a cover arranged on the steering wheel.
In yet another aspect of the present invention,
the particular device is a door handle;
the sensors are arranged to detect a user""s handgrip on the door handle; and
the interlocking unit releases a door lock when the pressure signature profile of a user""s handgrip matches a profile in storage.
In all of the above, comparator unit may count a number of attempts for authorization and disables the particular device after a predetermined threshold of successive non-matching pressure signature profiles have been compared.
In still another aspect of the present invention, the comparator unit counts a number of attempts for authorization and activates an alarm system after a predetermined threshold of successive non-matching pressure signature profiles have been compared.
A system for generating a pressure signature profile and comparing the pressure signature profile to a further pressure signature profile, which system can be used as a component of a handgun safety lock, the system comprises
a pressure actuated generator of electrical signals produced in response to applied pressure, applied pressure as a function of area, and applied pressure as a function of time;
a processing unit electrically connected to the generator,
the processing unit having a processor for developing a pressure signature profile from the electrical signals; storage for storing at least one pressure signature profile; and
a comparator for comparing the stored pressure signature profile to a further pressure signature profile.
Finally, a method for generating a pressure signature profile and comparing the pressure signature profile to a further pressure signature profile comprises the steps of:
(a) storing an authorized user""s pressure signature profile in a storage area;
(b) sensing the pressure of a user""s handgrip by pressure sensors and providing pressure to a comparator;
(c) compiling a pressure signature profile by the comparator based on the pressure sensed in step (b) with regard to: 1) positions of the sensors reporting a change in pressure, 2) an amount of change in pressure detected, and 3) pressure as a function of time;
(d) comparing the pressure signature profile compiled in step (c) with the pressure signature profile stored in step (a) to determine whether there is a matching profile;
(e) enabling access to a device if the comparison in step (d) matches to indicate a user is authorized.
Step (d) of the above method may include (i) maintaining a count of successive non-matching pressure signature profiles, and (ii) disabling the device if a number of successive non-matching reaches a predetermined threshold.
Step (b) of the above method may include (i) generating electrical signals from a source that generates electrical signals in response to applied pressure, applied pressure as a function of area, and applied pressure as a function of time.
Step (b) of the above method may also include sensing the pressure signature profile of a user""s handgrip on a handle of a firearm, a vehicle, or a door handle.